In such turbomachines, the rotor blades of the turbine stages are mounted on rotor disks by engaging male portions formed by the roots of the blades in cavities formed in the disks of the rotor, with such male/female engagement being of the dovetail or Christmas-tree type, for example, so that the blades are held radially for the disks of the rotor. Means are provided for preventing the roots of the blades from moving axially in the slots in the disks.
At rest, the axes of the blades are accurately perpendicular to the axis of rotation of the rotor.
It is found that the structure of the rotor is subjected to forces that are axial, radial, and tangential, and also to temperature gradients, thus leading to deformations that cause parasitic axial displacements of the free ends of the blades. Thus, while the turbomachine is in operation, the blades take up a configuration that is not perpendicular relative to the axis of rotation of the rotor. This configuration reduces the efficiency of the turbine, and thus reduces the performance of the turbomachine.